JPH0272609A - Sh capacitor - Google Patents

Abstract

PURPOSE:To improve dielectric strength by dividing the deposited electrode of an intermediate electrode into many electrode pieces in the longitudinal direction, and separating each electrode piece at the center in the lateral direction, and connecting these electrodes with a conduction part having a small width. CONSTITUTION:A first metallized film 1 is provided with a margin part 3 at the center in the width direction, and deposited electrodes 4 and 5 are provided at this both ends, and second metalized film 2 is provided with margin parts 6 and 7 at both margins in the width direction, and it is divided small in large numbers toward in the longitudinal direction of the film and is made into many electrode pieces 8. Further, a margin part 9 is provided at the center of this electrode pieces 8 so as to divide it into right and left electrodes 10 and 11, and also a thin deposited part 12 is provided between these electrodes 10 and 11 to make them conductive, and the first and second metallized films 1 and 2 are put one upon the other. Hereupon, even if insulation breakdown occurs in one electrode piece 8a, this breakdown is completed with the electrode piece 8a alone and it never extends to other electrode pieces. Hereby, withstand voltage can be elevated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a 5l-1 capacitor (self-healing capacitor) using a metallized film formed by forming vapor-deposited electrodes on a plastic film. , relates to a technique for providing an SH capacitor with high voltage resistance and safety by improving the pattern of the vapor-deposited electrode.

[Prior Art] An example of a capacitor using a metallized film is shown in FIG.

In FIG. 4, as shown in (A), a margin part 21 is provided on one edge in the width direction, and by vapor deposition by dividing into many pieces in the length direction, a large number of electrode pieces can be formed. A metallized film 23 formed with a divided electrode 22 consisting of (
As shown in B), the metallized film 23 of (A> and the metallized film 26 in which the machine part 24 is provided on the opposite edge and the vaporized electrode 25 is formed) are used, and these two metallized films are used. 23 and 26 are overlapped and wound as shown in (D>) to form a capacitor element.

In this case, instead of using the metallized film 26 of (B), the metallized film 23 of (A>) as shown in (C) is used.
A metallized film 29 is used, in which a margin part 27 is provided on the edge opposite to the metallized film 29, and a divided electrode 28 consisting of a large number of electrode pieces is formed by dividing the metallized film 29 into a large number of finely divided parts in the length direction and depositing them. Then, convert this to the metallized film 23 of (A>
There are also examples of overlapping.

After winding the metallized film as described above,
Metallicon is applied to the end face of the formed capacitor element, and electrodes are led out. In the capacitor thus obtained, for example, the metallized film 2 of (A>
If dielectric breakdown occurs at one point P of the divided electrode 22 of No. 3, the contact part of the electrode piece 22a with the metallcon, to which this breakdown point P belongs, will be separated by Joule heat due to the short circuit current, so the dielectric breakdown will spread to other parts. Capacitor function can be maintained without

By the way, as a means to further improve the withstand voltage performance of such a capacitor, is it possible to increase the film thickness using the configuration shown in Figure 4? Not. In other words, in the case of the configuration shown in Fig. 4, since the electrode is processed in parts, the circumferential line of the electrode is long, and the influence of electrode deterioration due to corona discharge becomes large, so even if the film thickness is increased, electrode deterioration is almost prevented. No effect can be obtained, and in the end the use is forced to be limited to low voltages.

As a capacitor designed to withstand high voltage without causing such problems, there is a conventional example shown in FIG. 5. In FIG. 5, a metallized film 32 with a margin part 30 provided at the center in the width direction and a vapor-deposited electrode 31 formed thereon, as shown in (△), and a metallized film 32 on both sides in the width direction as shown in (B). By superimposing the metallized film 35 on which the margin part 33 is provided and the vapor-deposited electrode 34 formed, and winding it as shown in (C), two capacitors C1 and C2 are formed as shown in (D). The structure is connected in series.

However, although the withstand voltage of the capacitor shown in Fig. 5 is considerably strengthened, it does not have self-healing properties like the capacitor shown in Fig. 4, so if dielectric breakdown occurs, this will spread to the whole. This will damage the capacitor function.

From this, it is conceivable to simply divide the vapor-deposited electrode 31 of the metallized film 32 in FIG. 5 (A>) in the length direction in order to obtain self-security like the capacitor shown in FIG. 4. 6(A), from the above viewpoint, a margin part 36 is provided at the center in the width direction, and both sides of this margin part 36 are divided into many pieces in the length direction for vapor deposition. The divided electrode 3 is made up of two rows of multiple electrode pieces.
The metallized film 38 formed with 7 is shown. Then, as shown in FIG. 6(B), the metallized film 38 of (A) and the vapor-deposited electrode 34 are provided with margin portions 33 on both edges in the width direction, having the same configuration as that of FIG. 5(B). When a capacitor was prototyped by combining the capacitor with the metallized film 35 formed thereon, the performance could not be improved by one level. Problems with the configuration shown in FIG. 6 and their reasons will be described below.

6. (A>(B) metallized film 38.3
When winding 5 in an overlapping manner, as shown in Fig. 6 (C),
It has a structure in which two capacitors C1 and C2 are connected in series. In such a capacitor, for example, if dielectric breakdown occurs at one point P of the divided electrode 37 of the metallized film 38 in (A), the first capacitor C1 side will be short-circuited at the electrode piece 37a to which this breakdown point P belongs. As a result, the entire voltage is applied to the second capacitor C2, and the overall capacitance is doubled due to the short circuit of one of the two stages in series, causing the circuit constant to go out of order. In this case, even if the first capacitor C1 is short-circuited, the function of the second capacitor C2 is maintained, so there is no short-circuit as a whole, and the current depends on the impedance of the second capacitor C2, resulting in destruction. There is insufficient current to separate the electrode piece 37a to which point P belongs from the metallicon.

Then, since the full voltage continues to be applied to the second capacitor C2 side, dielectric breakdown occurs at one point Q on the dividing electrode 37 on the second capacitor C2 side. At this point, the vapor deposited electrode 34 of the second metallized film 35 is removed from the breaking point P.
A short circuit current flows between the breakdown point Q and the breakdown point P
, Q belongs to either one of the electrode pieces 37a, 37b and is separated from the metallicon. At this time, the electrode pieces 37a, 37b
There are few cases in which both are disconnected at the same time, and usually the short circuit as a whole is eliminated by disconnecting one, so the remaining one is kept connected to the metal contact.

Therefore, the first and second capacitors Cz and C2
Since the full voltage is applied to one side and this is repeated thereafter, safety cannot be guaranteed.

On the other hand, instead of dividing the vapor deposited electrode 31 of the metallized film 32 in FIG. 5(A) in the length direction, the vapor deposited electrode 24 of the metallized film 35 in FIG. In FIG. 7(B), margin portions 39 are provided on both edges in the width direction, and the margin portions 3
A metallized film 41 is shown in which divided electrodes 40 consisting of two rows of multiple electrode pieces are formed by dividing the space between 9 into many pieces in the length direction and depositing them.

However, this metallized film 41 in FIG. 7(B)
and a metallized film 32 having the same configuration as in FIG. 5(A) and having a margin portion 3Q at the center in the width direction and forming a vapor deposited electrode 31 as shown in FIG. 7(A>). As shown in FIG. 7(C), since the separation electrode 4o is not separated, there is no point in forming the separation electrode 40.

Furthermore, by combining the metallized film 38 having the divided electrode 37 shown in FIG. 6 (A>) and the metalized film 41 having the divided electrode 40 shown in FIG. , the breaking point P of C2.

Q is not far apart, and the first capacitor C
Due to the short-circuiting of the breakdown point P of the second capacitor C2, the full voltage is no longer applied to the entire second capacitor C2 side, so that the characteristics of the entire capacitor can be considerably improved. However, in this case, in the winding operation, it is extremely difficult to completely match the divided electrodes 37, 40 of both metallized films 38, 41, and it is impossible to avoid the misalignment that occurs with winding. Adjacent electrodes tend to come into contact with each other, making it impossible to completely prevent a chain reaction of dielectric breakdown.

[Problem to be solved by the invention] As explained above, in conventional capacitors, 2
If you attempt to obtain a capacitor with increased voltage resistance and high safety by configuring several capacitors connected in series, even if one of the capacitors attempts to self-recover in the event of a short circuit, the remaining capacitor will Since they are connected in series, short-circuit current does not flow through the capacitor as a whole, making it difficult to recover instantly due to lack of energy. Moreover, since a current equivalent to twice the rated current continues to flow through the short circuit, the damage will increase.

Roughly speaking, the full voltage of the two stages in series is applied to the capacitor on the functioning side, and if one of the two stages in series is shorted, the overall capacitance doubles, causing the circuit constants to go awry. .

Then, since the full voltage of two stages in series continues to be applied to one capacitor, dielectric breakdown occurs at weak points that are randomly present in the element.

Even if a short-circuit current flows for the first time at this point and instantaneously recovers, if one of the breakdown points recovers, the full voltage of the two series series will be applied to only one capacitor again, resulting in such overvoltage and dielectric breakdown. It is easy to fall into repetition.

The present invention was proposed in order to solve the shortcomings of the prior art, and its purpose is to provide a system with high voltage resistance, no influence on circuit constants, and excellent safety. An object of the present invention is to provide an SH capacitor.

[Means for Solving the Problems] The SH capacitor according to the present invention has a structure in which two stages are connected in series by using vapor-deposited electrodes having a margin at the center in the width direction. This is an improved version of the vapor-deposited electrode that becomes the electrode.

That is, in the present invention, the vapor-deposited electrode on the side that will become the intermediate electrode has margin portions on both edges in the width direction, is finely divided into many pieces in the length direction, and each divided electrode piece is It is characterized in that it is divided into left and right parts at the center in the width direction, and the left and right electrodes are connected by a conductive part with a small width.

[Function] The function of the SH capacitor of the present invention having the above-mentioned configuration is as follows.

That is, in the present invention, since the electrodes on both sides of a large number of electrode pieces constituting a vapor deposition electrode serving as an intermediate electrode are connected in series to form a capacitor, the total number of electrode pieces is The wiring structure consists of a large number of sets of two-stage series extremely small capacitance capacitors arranged in parallel. In the present invention having such a wiring structure, if dielectric breakdown occurs in one electrode of one electrode piece, only the minimal capacitance capacitor of this electrode part is short-circuited, and the connected electrode on the opposite side short-circuits the electrode. Twice the voltage is applied to the extremely small capacity capacitor, causing dielectric breakdown on this electrode side as well.

As a result, a short-circuit current flows through this electrode piece, and the two-stage series minimal capacitor of the same product self-recovers by instantaneous discharge.

In this case, even if self-recovery is not possible, a short-circuit current flows between the electrodes on both sides of the electrode piece, so that the thin conductive portion connecting the electrodes is burned out and an open circuit occurs. As a result, only the portion of the electrode piece having the picture electrode loses its capacitor function, and many other electrode pieces operate without any problem, so that the capacitor function as a whole can be maintained. Therefore, in the present invention, even if dielectric breakdown occurs, the short-circuit current flows only to the electrode piece where dielectric breakdown has occurred, so the entire capacitor will not be short-circuited and will self-recover or the electrode piece will only is separated.

[Example] Below, one example of the SH capacitor according to the present invention will be described as a first example.
This will be explained in detail with reference to the drawings.

First, in this embodiment, two metallized films 1 and 2 as shown in FIGS. 1(A) and 1(B) are used.

The first metallized film 1 shown in FIG.
5. As the material of the plastic film serving as the base of the metallized film 1, known polypropylene, polyethylene terephthalate, etc. are used, and as the material of the vapor-deposited metal, zinc, aluminum, etc. are used.

The second metallized film 2 shown in FIG. 1(B) has margin parts 6 and 7 on both edges in the width direction, and is finely divided into many pieces in the length direction of the film to form a large number of electrode pieces 8. Roughly, a margin part 9 is provided in the center of this electrode piece 8,
This electrode 10 is divided into left and right electrodes 10 and 11.
．． Between 11 and 11, a thin vapor deposition band 12 is provided to provide electrical continuity.

Moreover, the width of the second metallized film 2 is narrower than that of the first metallized film 1 by 1 to 2 mm.

First and second metallized films 1 formed as described above
, 2 are placed one on top of the other and wound as shown in FIG.

As a result, as shown in FIG. 1 (D>), a connection structure is obtained in which two capacitors C1 and C2 are connected in series. In this case, half of the voltage is borne by each capacitor C1 and C2.

The operation of this embodiment having the above configuration is as follows.

First, when performing voltage treatment or withstanding voltage test after manufacturing,
When dielectric breakdown occurs at the weak point between the electrodes, self-recovery is possible. That is, between the vapor-deposited electrode 4 of the first metallized film 1 and the electrode 10a of the second metallized film 2 constituting the first capacitor C1, dielectric breakdown occurs between opposing points P and P-. If this dielectric breakdown occurs and is not recovered, a voltage equivalent to two stages in series will be applied to the electrode 11a connected to the electrode 10a in the vapor deposition zone 12, causing dielectric breakdown between Q and Q-. In this case, since a short circuit current flows, the short circuit between breakdown points P and P- or between breakdown points P and P- or between breakdown points P and Q and Q- will self-recover by instantaneous discharge, but between breakdown points P and P- and breakdown point Q,
In many cases, both Q and Q do not recover at the same time, so high voltage continues to be applied to the recovered side, leading to irreversible destruction. In that case, a high short-circuit current flows through the thin vapor deposition band 12a connecting the electrodes 10a and 11a to which these breakdown points belong, so that this vapor deposition band 12a becomes a fuse, as shown in FIGS. 1(E) and (F). It plays the role of cutting. That is, in this embodiment, one electrode piece 8a
Even if dielectric breakdown occurs in the electrode piece 8, this breakdown
Since it is completed only with a and does not spread to the outer electrode pieces, the capacitor as a whole consists of electrode pieces 8 with weak points.
Only part a is separated, resulting in an assembly of electrode pieces with no electrical weaknesses and a constant withstand voltage. Further, this embodiment similarly acts on partial dielectric breakdown that occurs during use.

Therefore, in this embodiment, there are no low variations in withstand voltage, and the withstand voltage increases. FIG. 3 is a diagram showing a specific distribution of dielectric breakdown voltage. That is, in FIG. 3, a polyethylene terephthalate film with a thickness of 5 μm and a width of 5 Qmm is used as the first metallized film 1, and a polypropylene film with a thickness of 5 μm and a width of 48 mm is used as the second metallized film 2. This is a diagram showing the distribution of dielectric breakdown voltage between the conventional example (A> and the present invention (B)) when aluminum vapor deposition is applied to It can be seen that the average value of the present invention is 1650V, which is an increase in withstand voltage of about 20%.

Further, in the conventional technique, the withstand voltage failure rate was approximately 0.4%, whereas in this example, it was confirmed that the withstand voltage failure rate was 0%.

Furthermore, a problem unique to capacitors with a two-stage series structure is that when one capacitor is short-circuited, the full voltage is applied to the remaining capacitor, which can cause damage and double the capacitance. However, in this example, as mentioned above, the breakdown can be intermittent at the electrode piece where the insulation breakdown occurred, so the breakdown does not spread, and the short-circuit current However, since the current flows only through the electrode piece, the capacitance of the capacitor as a whole does not double, and there is no risk of affecting the circuit constants.

As described above, in this embodiment, dielectric breakdown can be locally recovered or completed, and recovery performance in the event of a short circuit is good.
The entire capacitor is completely resistant to failure and has excellent safety.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be widely used without any restrictions such as the type of vapor-deposited metal or the type of film used in the metallized film.

In addition, instead of using two metalized films, the vapor deposition electrodes shown in FIGS. Almost the same effect can be obtained even if a plastic film is stacked on top of the other.

Roughly speaking, it is also possible to construct a structure in which the vapor deposition electrode shown in FIG. 1(A) is subdivided into a large number of parts in the length direction as shown in FIG. 6(A).

On the other hand, in FIG. 1(B), the electrodes 1 on both sides of the electrode piece 8
It is also possible to provide not one but a plurality of vapor deposition zones 12 connecting the 0.11.

Incidentally, in the above embodiment, a case of a two-stage series type structure was described, but the present invention can also be applied to a four-stage series type capacitor as shown in FIG. The metallized film 13 shown in FIG. 2 <A> has two margins 14 at two central locations in the width direction to divide the film surface into three parts, and on both sides are the vapor-deposited electrodes shown in FIG. 1 (A>). Similar undivided vapor deposition electrodes 15 and 16 are provided, and a divided electrode similar to that shown in FIG. 1(B) is provided between them.

Further, the metallized film 17 shown in FIG. 2 (8) has margin parts 18 on both edges in the width direction, a margin part 19 in the center part in the width direction, and a margin part 18 and 19 formed between the margin parts 18 and 19. A divided electrode similar to that shown in FIG. 1(B) is provided on each of the two surfaces. When four stages are connected in series in this way, not only the same effect can be achieved, but also the withstand voltage can be greatly improved.

That is, the present invention is similarly applicable to general multi-stage series capacitors with two or more stages, and can be applied to capacitors with excellent voltage resistance.

[Effects of the Invention] As explained above, according to the present invention, in an SH capacitor having a structure in which two stages are connected in series, the vapor deposited electrode of the intermediate electrode is formed into a large number of electrode pieces in the length direction, and each Due to the simple structure of dividing the electrode piece into left and right parts at the center in the width direction and connecting the electrodes with a conductive part with a small width, it has higher voltage resistance than conventional products and does not affect the circuit constants. Therefore, it is possible to provide an SH capacitor that is free from oxidation and has excellent safety.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a basic embodiment of the SH capacitor according to the present invention, in which (A) is a plan view showing the first metallized film, and (B) is a plan view showing the second metallized film serving as the intermediate electrode. A plan view showing the film, (C) a perspective view showing the capacitor element in the middle of winding, (D> is a wiring diagram, (E) a plan view showing the safety operation, (F) is also a wiring diagram, (G) (H) is a cross-sectional view showing a state in which the first and second metallized films are overlapped;
is a wiring diagram of (G). FIG. 2 is a diagram showing an applied embodiment of the SH capacitor according to the present invention, in which (A> is a plan view showing the first metallized film, and (B) is a plan view showing the second metallized film. Figure 3 (C) is a sectional view showing the state in which the first and second metallized films are overlapped, and (D) is a wiring diagram of (C). Figure 3 shows the dielectric breakdown of the conventional example and the present invention. These are graphs showing voltage distribution, where (A) is the conventional example and (B) is the present invention. Figures 4 to 7 are diagrams showing different conventional capacitors. 1... 1st metallized film, 2... second metallized film, 3, 6, 7, 9, 14, 18. 19... margin portion, 4, 5, 15. 16... vapor deposited electrode, 8...・
・Electrode piece, 10.11... Electrodes on both sides of the electrode piece, 12
... Vapor deposition zone, 13.17 ... Metallized film, P. P-, Q, Q-... Breaking point.

Claims (1)

[Claims] First and second plastic films are provided, a first vapor-deposited electrode is formed on one side of the first plastic film, and one side of the second plastic film or the remaining part of the first plastic film is provided. In an SH capacitor in which a second vapor-deposited electrode is formed on one side, and the first and second plastic films are overlapped and wound, the first vapor-deposited electrode has a margin portion at the center in the width direction. The second vapor deposition electrode has a width narrower than that of the first vapor deposition electrode, and has margin portions at both edges in the width direction,
In addition, it was divided into many pieces in the length direction, and further, each divided electrode piece was divided into left and right parts at the center in the width direction, and the left and right electrodes were connected by a conductive part with a small width. SH capacitors are characterized by: